This invention relates to a cyclopentenone compound represented by the following formula (I): ##STR2## [which will be hereinafter referred to as compound (I), and compounds with other formulae will also be referred to in the similar manner] and to a process for producing compound (I) from antibiotic XK-213.
antibiotic XK-213 is an antitumor antibiotic produced by Actinomycetes and is disclosed in Japanese Published Unexamined patent application No. 59777/1981.
Compound (I) is a compound having a cytocidal effect on tumor cells.